What is the difference between blender render and blender game?
If you are making a still render or animation, then you most likely want to use the rigid body physics in the 3D view.

If you are making a game or a program that users will interact with in some way, then you most likely want the game engine.



Not too long ago blender didn't have any way to simulate rigid body physics outside of the game engine, and there are still lots of tutorials floating around from before that time.